Question

Account for the following 

1. Aluminium undergo slow corrosion than iron.

2. H₂ – O₂ fuel cell is more useful than other cells

Answer 1

1. Aluminium, copper, silver also undergo corrosion but at a slower rate than iron. 

For eg., let us consider the reduction of Aluminium 

Al_(s) → Al³⁺_(aq) + 3e^- 

Al³⁺ which reacts with oxygen in air to form a protective coating of AI₂O₃ . This coating act as a protective film for the inner surface. So further corrosion is prevented. 

2. H₂ – O₂ fuel cell is more advanced. Because it is highly efficient. it is pollution free. In this, H₂ – O₂ fuel cell, energy of combustion of fuel is directly converted to electrical energy